Image display medium, image-forming method, image-forming apparatus and initializer

Abstract

Provided are an image display medium which satisfies a safety and a high-speed response and which is capable of repetitive rewriting, an image-forming method in which an image can be formed on the image display medium, an image-forming apparatus, and an initializer. In the image display medium, conductive particles and insulating particles are interposed between a display substrate and a non-display substrate having a positive charge-transporting property. An electrostatic latent image adapted to the image is formed on an electrostatic latent image carrier. A bias voltage is applied to a counter electrode. Positive charges (non-image portion) on the electrostatic latent image carrier are transferred to the display substrate to charge the conductive particles. The charged conductive particles are moved toward the non-display substrate. In the uncharged portion (image portion) of the electrostatic latent image carrier, positive charges are transferred to the non-display substrate from the counter electrode to charge the conductive particles. The charged conductive particles are moved toward the display substrate.

What is claimed is:  
     
       1. An image display medium comprising: 
       a pair of substrates, at least one of which has a charge-transporting property and which has a surface that is exposed to an area external to the display medium; and  
       plural types of particle groups contained between the substrates and movable by an electric field applied from outside, the plural types of particle groups being different from each other in at least one of color and property, at least one of the plural types of particle groups having particles in contact with at least one of the pair of substrates when the electric field is applied, wherein at least one substrate having the charge-transporting property allows charges to pass from the area external to the display medium to an area internal to the display medium through that at least one substrate.  
     
     
       2. The image display medium as claimed in  claim 1 , wherein at least one type of the particle groups is of conductive particles. 
     
     
       3. The image display medium as claimed in  claim 1 , further comprising: 
       a cell structure composed of cells of a predetermined shape between the substrates.  
     
     
       4. The image display medium as claimed in  claim 3 , wherein at least one type of the particle groups is of conductive particles and the conductive particles are contained in the cells corresponding to respective plural colors forming a multicolor image. 
     
     
       5. An image-forming method in which the image is formed on an image display medium comprising a pair of substrates at least one of which has a charge-transporting property and which has a surface that is exposed to an area external to the display medium and plural types of particle groups contained between the substrates and movable by an electric field applied from outside, the plural types of particle groups being different from each other in at least one of color and property, the method comprising the steps of: 
       forming on a latent image carrier an electrostatic latent image corresponding to an image; and  
       generating an electric field between a counter electrode and the latent image carrier, the counter electrode being mounted in a position facing the latent image carrier such that the image display medium can be positioned therebetween, at least one of the plural types of particle groups having particles in contact with at least one of the pair of substrates when the electric field is applied, wherein the at least one substrate having the charge-transporting property allows charges to pass from the area external to the display medium to an area internal to the display medium through that at least one substrate.  
     
     
       6. An image-forming apparatus for forming an image on an image display medium, comprising: 
       the image display medium comprising a pair of substrates at least one of which has a charge-transporting property and which has a surface that is exposed to an area external to the display medium and plural types of particle groups which are contained between the substrates and movable by an electric field applied from outside, the plural types of particle groups being different from each other in at least one of color and property;  
       a latent image carrier;  
       electrostatic latent image forming means for forming on the latent image carrier an electrostatic latent image corresponding to an image; and  
       a counter electrode for generating an electric field between itself and the latent image carrier, the counter electrode being mounted in a position facing the latent image carrier such that the image display medium can be positioned therebetween, at least one of the plural types particle groups having particles in contact with at least one of the pair of substrates when the electric field is applied, wherein the at least one substrate having the charge-transporting property allows charges to pass from the area external to the display medium to an area internal to the display medium through that at least one substrate.  
     
     
       7. The image-forming apparatus as claimed in  claim 6 , wherein a bias voltage is applied to the counter electrode. 
     
     
       8. The image-forming apparatus as claimed in  claim 6 , wherein at least one type of the particle groups is of conductive particles, the image-forming apparatus further comprising: 
       charging means for previously charging the conductive particles.  
     
     
       9. The image-forming apparatus as claimed in  claim 6 , wherein at least one type of the particle groups is of conductive particles, the image-forming apparatus further comprising: 
       charging means for previously charging the conductive particles by applying at least one of a DC voltage and an AC voltage to the substrates.  
     
     
       10. The image-forming apparatus as claimed in  claim 6 , wherein at least one type of the particle groups is of conductive particles, the image-forming apparatus further comprising: 
       charging means for previously charging the conductive particles, the charging means being made of an elastic material and applying at least one of a DC voltage and an AC voltage to the substrates in a state closely adhered to the image display medium.  
     
     
       11. The image-forming apparatus as claimed in  claim 6 , wherein at least one type of the particle groups is of conductive particles, the image-forming apparatus further comprising: 
       charging means for previously charging the conductive particles, the substrate having the charge-transporting property being earthed before conducting the charging by the charging means.  
     
     
       12. An image-forming apparatus for forming an image on an image display medium, comprising: 
       the image display medium comprising a pair of substrates at least one of which has a charge-transporting property and which has a surface that is exposed to an area external to the display medium and plural types of particle groups which are contained between the substrates and movable by an electric field applied from outside, the plural types of particle groups being different from each other in at least one of color and property, at least one of the plural types of particle groups having particles in contact with at least one of the pair of substrates when the electric field is applied, wherein the at least one substrate having the charge-transporting property allows charges to pass from the area external to the display medium to an area internal to the display medium through that at least one substrate;  
       a latent image carrier;  
       electrostatic latent image forming means for forming on the latent image carrier an electrostatic latent image corresponding to an image;  
       a counter electrode for generating an electric field between itself and the latent image carrier, the counter electrode being mounted in a position facing the latent image carrier such that the image display medium can be positioned therebetween;  
       inputting means for inputting whether a medium on which the image is formed is the image display medium for an image-recording medium;  
       developing means for developing the electrostatic latent image formed by the electrostatic latent image forming means with a toner when the result inputted by the inputting means is the image-recording medium;  
       transferring means for transferring the toner image developed by the developing means onto the image-recording medium; and  
       fixing means for fixing the toner image transferred onto the image-recording medium.  
     
     
       13. The image-forming apparatus as claimed in  claim 12 , wherein the inputting means is medium-detecting means for detecting whether the medium on which the image is formed is the image display medium or the image-recording medium. 
     
     
       14. The image-forming apparatus as claimed in  claim 12 , wherein the transferring means is the counter electrode. 
     
     
       15. The image-forming apparatus as claimed in  claim 12 , wherein when the result inputted by the inputting means is the image display medium, the fixing by the fixing means is not conducted. 
     
     
       16. The image-forming apparatus as claimed in  claim 12 , further comprising: 
       development-stopping means for stopping the development by the developing means when the result inputted by the inputting means is the image display medium.  
     
     
       17. An initializer for initializing the image display medium as claimed in  claim 1 .